RU2793712C2 - Rotating contact device - Google Patents

Abstract

FIELD: electrical engineering.

SUBSTANCE: rotating contact device consists of stationary and rotating contacts forming contact pairs, located in a horizontal plane relatively to a vertical axis of rotation of rotating contacts collected in a packet, while stationary contacts are flat two-element plugs of springy material, intended for provision of a contact with rotating rings, freely installed with a middle part on the axis of dielectric material, which is located in parallel to the axis of rotation of rotating rings.

EFFECT: reduction in noises, increase in the reliability and stability of contact resistance during rotation.

3 cl, 1 dwg

Description

The invention relates to the field of instrumentation and can be used to transmit electrical signals, including coded information signals from a stationary part of an object to its rotating part.

Known rotating contact devices (VKU), containing a rotating ring in contact with a fixed elastic conductive comb in the form of bent petals [1].

The disadvantage of the known device: it has a reliable multi-point electrical contact, but does not provide the bandwidth necessary for broadcasting high-speed interfaces, because has a large transient electrical capacitance between adjacent contact pairs.

The closest in technical essence to the proposed rotating contact device, taken as a prototype, is a brush collector assembly, consisting of a package of flat brush holders separated by insulating spacers and elastic brushes made in the form of pieces of round wire, one of the ends of which is rigidly fixed to the corresponding brush holders, and the middle parts are in contact with the corresponding slip rings of the collector [2].

The disadvantage of the rotating contact device, taken as a prototype, is the presence of noise in the signal due to the changing clamping force of the fixed contact of the brush holder package with the corresponding slip ring of the collector, since the change in clamping force during rotation occurs due to ovality (defect in the processing of the collector ring) and misalignment (package build defect).

The technical result of the invention is to reduce noise, increase the reliability and stability of the contact resistance during rotation, due to:

- a decrease in the variable component due to a change in the contact electrical resistance at diametrically located points of electrical contact of a fixed two-element plug and a rotating ring, due to the oval shape (manufacturing error) of the contact rings of the collector and misalignment of the rotating rings (due to the collector assembly error);

- reducing the amplitude of noise caused by a change in the voltage drop across the contact electrical resistance at diametrically located points of electrical contact of a fixed two-element plug and a rotating collector ring;

- flat elastic contacts in the form of two-element forks are made of a springy material, for example, beryllium bronze, and to improve the springy properties, the symmetry axis of the plug elements coincides with the direction of rolling of the springy material, because in this direction, the springy material has maximum springy properties;

- increasing the dynamic stability of the contact electrical resistance during rotation is achieved by eliminating the variable component due to the oval shape (manufacturing error) of the contact rings of the collector, misalignment of the rotating rings (due to the assembly error of the collector), by fixing each flat fixed contact at one point on the axis parallel to the axis of rotation of the contact rings of the collector, which allows a flat fixed contact to freely track the ovality and misalignment of the collector ring, thereby reducing the variable component of the contact electrical resistance.

Indeed, for the case of fixing a flat elastic contact rigidly, i.e. at least at two points in the plane of rotation of the contact rings of the collector and if we assume that the change in the contact electrical resistance _rm during rotation occurs according to a sinusoidal law with a rotation frequency co, we can write a general expression for the electric current in the contact circuit

,

,

where R _e is the electrical resistance of the load;

E - emf direct current source;

r ₀ - contact electrical resistance at rest;

r _m - variable electrical resistance of the electrical contact caused by rotation;

r _a - internal electrical resistance of the DC source. Denoting the resistance R _e + r _a + r ₀ \u003d R, we get:

является индексом модуляции контактного электрического сопротивления. Введем его в формулу (2), получим:Attitude

is the modulation index of the contact electrical resistance. We introduce it into formula (2), we get:

For small values of the modulation index in equation (3), the terms enclosed in brackets, starting from the second and further, can be neglected, then

or

From equation (5) it can be seen that during rotation in the contact circuit, a pulsating current with a constant

and variable component

or

The amplitude of the variable component is expressed as

Consequently, the voltage on the contact during rotation, in addition to the constant component, has a parasitic component proportional to the modulation index and deteriorating the signal-to-noise ratio, which will necessitate an increase in the bandwidth of the information channel.

Thus, the exclusion of the variable component by changing the design of the brush holder package makes it possible to increase the stability of the electrical resistance of the contact and improve the signal-to-noise ratio of the information signal transmission channel.

To reduce the amplitude of noise and increase the signal-to-noise ratio due to a change in the contact electrical resistance during rotation, additional two-element fixed plugs are installed at diametrically located points of electrical contact between the fixed two-element plug and the rotating ring so that electrical contact with one rotating ring is simultaneously carried out in points located along the outer circumference of the ring at intervals of multiples of 360°/2k, while the frequency of the variable noise component ω/60 (Hz) increases, and the modulation index decreases by 2k times, which contributes to a decrease in the noise amplitude by the same factor, here k = 1, 2, 3 … number of additional two-piece fixed plugs.

The design of a rotating contact device makes it possible to obtain additional useful properties for contact pairs operating in channels for the transmission of coded information, for which, in addition to the stability of the contact resistance, the stability of the channel bandwidth is also required. The formation of the desired channel bandwidth is achieved by changing the insulating gap between adjacent contact pairs involved in the transmission of encoded information, using insulating spacers of the required thickness and relative dielectric constant.

In FIG. 1 shows a rotating contact device.

The device contains a collector (pos. 1) with coaxially arranged slip rings (pos. 2) (rotating part) and a package of brush holders (pos. 3) with elastic flat contacts made in the form of two-element forks (pos. 4) (fixed part). In the middle part of the plugs there is a hole through which the brush holder axle (pos. 5) is passed, made of insulating material, and the side parts of the plugs cover the contact rings of the commutator.

The device works as follows. When the collector (pos. 1) rotates, the contact rings (pos. 2) coaxially located in it slide with their outer surface along elastic flat contacts made in the form of two-element plugs (pos. 4) assembled in a package (pos. 3), thus thereby making electrical contact between the fixed (pos. 4) and rotating part (pos. 2), and each two-element fork has one point of support on the axis (pos. 5) parallel to the axis of rotation of the collector and has the ability to move freely in the horizontal sector of "misalignment" and "ovality" of the corresponding collector slip ring.

The technical and economic efficiency of the invention lies in the fact that

Reducing the variable component by changing the design of the brush holder package makes it possible to increase the stability of the electrical resistance of the contact, improve the signal-to-noise ratio of the information signal transmission channel by installing additional two-element plugs, and thereby increase the speed of digital data transmission in the electrical circuits of the rotating contact device.

The proposed design of a rotating contact device makes it possible to obtain additional useful properties for contact pairs operating in coded information transmission channels, for which, in addition to contact resistance stability, channel bandwidth stability is also required. The formation of the desired channel bandwidth is achieved by changing the insulating gap between adjacent contact pairs involved in the transmission of encoded information, using insulating spacers of the required thickness and relative dielectric constant.

INFORMATION SOURCES

1 RF patent No. 2267841, IPC H01R 39/00, publ. 01/10/2006

2 RF patent No. 2111586, IPC H01R 39/00 publ. May 20, 1998

Claims (3)

1. A rotating contact device consisting of fixed and rotating contacts forming contact pairs located in a horizontal plane with respect to the vertical axis of rotation of the rotating contacts assembled in a package and characterized in that the fixed contacts are flat two-element plugs having electrical contact in two diametrically opposite points of the lateral surface of the rotating contact rings, and each fixed contact, when forming a package of contact pairs, is freely installed by its middle part on the axis of the dielectric material, which is located parallel to the axis of rotation of the rotating rings. 2. A rotating contact device according to claim 1, characterized in that additional fixed contacts are installed in the package of contact pairs, separated from each other by insulating spacers, so that electrical contact with the same rotating contact is simultaneously carried out at diametrically opposite points, located on the side surface of the contact ring at intervals of multiples of 360°/2k, where k=1, 2, 3 ... the number of fixed contacts. 3. A rotating contact device according to claim 1, characterized in that the electrical capacitance between adjacent contact pairs in the package is formed by changing the distance between these contact pairs using insulating spacers of a certain thickness and relative dielectric constant.

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